BRUEL & KJAER 4226 User Manual
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BRUEL & KJAER 4226 User Manual

Multifunction acoustic calibrator
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USER MANUAL
Multifunction Acoustic Calibrator
Type 4226
BE 1041 – 12
English

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Summary of Contents for BRUEL & KJAER 4226

  • Page 1 USER MANUAL Multifunction Acoustic Calibrator Type 4226 BE 1041 – 12 English...
  • Page 3 Multifunction Acoustic Calibrator Type 4226 User Manual BE 1041 – 12 January 2019 www.bksv.com...
  • Page 4 Health and Safety Considerations Electrical Hazards This apparatus has been designed and tested in accordance Warning: Any adjustment, maintenance and Safety with IEC/EN 61010 – 1 ANSI/UL 61010 – 1 repair of the open apparatus under voltage must Requirements for Electrical Equipment for Measurement, be avoided as far as possible and, if unavoidable, Control and Laboratory Use .
  • Page 6 Brüel & Kjær has made every effort to ensure the accuracy of Brüel & Kjær and all other trademarks, service marks, trade the information contained in this document. No responsibility names, logos and product names are the property of is accepted for any errors or omissions herein. It is the Brüel &...

  • Page 7: Table Of Contents

    What is Multifunction Acoustic Calibrator Type 4226? ............1 How the Calibrator Works ......................2 CHAPTER 2 The Parts of Multifunction Acoustic Calibrator Type 4226 ............7 What’s Included ........................7 Controls on the Front Panel...................... 8 Controls on the Side Panel...................... 12 CHAPTER 3 Operation ..........................

  • Page 9: Introduction

    1.1.1 General Use Type 4226 is a laboratory precision instrument. Its size and the included power supply of four alkaline cells make the instrument easy to use in-situ (for example, with a sound level meter or a large measurement setup in an anechoic chamber). The simplicity of use also makes it highly portable;...

  • Page 10: How The Calibrator Works

    Multifunction Acoustic Calibrator Type 4226 – User Manual How the Calibrator Works Fig.1.2 shows a block diagram of Type 4226. A crystal-locked sine generator produces signals of very stable frequency. These signals pass through a variable gain amplifier and are sent to the transducers located in the Type 4226’s acoustic coupler.
  • Page 11 Checking the Frequency Response Type 4226 delivers a very stable tone with a frequency varying from 31.5 Hz to 16 kHz in octave steps, with an extra tone at 12.5 kHz. The 12.5 kHz tone is used for checking the highest frequency specified for type 1 sound level meters.
  • Page 12 1.2.7 Calibrating a Noise Dose Meter Noise dose meters are calibrated using one of the three calibrated levels and Type 4226’s built- in timer. The timer automatically switches off the stabilised SPL after 30 s. This gives a well- defined noise dose to calibrate the meter. The frequency response of the noise dose meter is checked by applying the inverse A-weighted level and by changing the signal frequency.
  • Page 13 1.2.9 Using an External Generator A generator with an output voltage between 0.5 V and 1.5 V can be connected to Type 4226. The calibrator regulates the level in the coupler to ensure a constant SPL relative to the inverse reference microphone response.
  • Page 14 Multifunction Acoustic Calibrator Type 4226 – User Manual...

  • Page 15: The Parts Of Multifunction Acoustic Calibrator Type 4226

    2.1.1 Using the Coupler Type 4226 and Coupler UA-0915 are supplied as a matched pair in that they are factory-adjusted to provide a constant sound pressure when the coupler is loaded by a Brüel & Kjær Type 4180 microphone. The same serial number appears on both items to help ensure that they are always used together as a matched pair.

  • Page 16: Controls On The Front Panel

    The front panel of Type 4226 • Power: Switch Type 4226 On or Off. Type 4226 is powered by four 1.5 V batteries • Batt. Low: The LED lights up when the battery voltage is too low. When this happens, replace the four cells in the battery drawer according to the instructions given in section 3.2.
  • Page 17 CHAPTER 2 The Parts of Multifunction Acoustic Calibrator Type 4226 corrections for the reference microphone are not applied. The compression (feedback) loop, however, remains in force to ensure a stable sound level in the coupler • Frequency Step: With the Function switch in Test Level or Calibration mode, use these buttons to step Up or Down the test signal frequencies or to select to use an external generator.
  • Page 18 Multifunction Acoustic Calibrator Type 4226 – User Manual • Microphone: Use this switch to set the microphone type under calibration. When correctly set, a free-field frequency response check may be made. Corrections for each microphone group as well as the 0 ° incidence free-field responses are automatically applied to the signal in the coupler.
  • Page 19 CHAPTER 2 The Parts of Multifunction Acoustic Calibrator Type 4226 • Sound Level dB: Use this switch to select the sound level (within the tolerances given in Appendix A) you want to check the calibration of your instrument: – 94: A properly calibrated instrument with linear frequency weighting should read within its frequency range, and within its tolerances, 94 dB at all selected discrete frequencies.

  • Page 20: Controls On The Side Panel

    10 instead of 3. Free-field response corrections are still applied. The insertion of a mini-jack plug will automatically isolate the coupler from Type 4226. The output signal from here is for checking the electronic functions of the sound level meter from the point of the microphone input •...

  • Page 21: Operation

    Operation Environmental Conditions Type 4226 operates properly in temperatures ranging from –10 to +50 °C (+14 to 122 °F) and in conditions of up to 90% relative humidity (tested at 30 ° C). The tolerances specified in Appendix A are ensured at 20 °C (68 °F) and 1013 hPa.

  • Page 22: Preparing For Acoustic Calibrations

    The stability of Type 4226, however, is so high that any corrections applied will be very small, if not negligible. The corrections to apply to a 1000 Hz reference level of 94 dB generated in Type 4226’s coupler for temperatures and pressures that depart from 20 °C and 1013 hPa are...
  • Page 23 2) Insert the microphone. Make sure it reaches the stop ring of the adapter. 3) Lock the microphone in place by tightening the adapter (turn it approximately ¼ to ¾ of a of a revolution in a clockwise direction. Fig.3.3 Type 4226 with its coupler mounted on the microphone of Hand-held Analyzer...

  • Page 24: Frequency Response Calibrations Of Listed Microphones

    Multifunction Acoustic Calibrator Type 4226 – User Manual Frequency Response Calibrations of Listed Microphones Before a Calibration 1) Using the switch, switch On Type 4226. Power 2) Check the battery condition. The LED should remain off. You can switch Off the Batt.

  • Page 25: Frequency Response Calibrations Of Unlisted Microphones

    This will indicate what corrections need to be applied to the Type 4226 results for each of its selected frequencies. These corrections will be valid for all other microphones of the same type, that is, the same geometry, but not of other types. This is because...

  • Page 26: Checking The Differential Level Linearity Of Brüel & Kjær Sound Level Meters

    Checking the Differential Level Linearity of Brüel & Kjær Sound Level Meters Type 4226 may be used to check that the differential level linearity of a Brüel & Kjær sound level meter is within the tolerances specified by IEC and ANSI standards. Table 3.2 shows these tolerances for the two specified frequency ranges for types 0, 1 and 2 sound level meters.

  • Page 27: Checking The "F" And "S" Time Weighting

    Table 3.2. Checking the “F” and “S” Time Weighting Type 4226 may be used to check the F (fast) and S (slow) time weighting functions of sound measuring instruments, measuring amplifiers, level recorders, etc. Type 4226 does this by providing the requisite test tonebursts for determining the onset transient characteristics of F and S detectors.
  • Page 28 Test Level. This will enable the buttons. Function Frequency Step 4) The 2 kHz LED on Type 4226 will light up. This is the default frequency setting for this test. Other frequencies may be selected using the buttons. Frequency Step 5) When conditions are stable, rotate the knurled wheel on Type 4226 until the Sound level meter displays a constant level of 106.0.

  • Page 29: Checking The Crest Factor Handling

    ±1 – On Type 4226, the rms level of the applied test signal is always the same as that set up using the Test Level facility. The magnitude of an error is equal to any deviation observed in the measured...
  • Page 30 Function Frequency Step 4) The 2 kHz LED on Type 4226 will light up. This is the recommended frequency setting for this test. 5) When conditions are stable, note the reading displayed on the sound level meter, if necessary rotate the knurled wheel on Type 4226 until a convenient value is displayed.

  • Page 31: Calibrating A Noise Dose Meter

    Table 3.6 and Table 3.7 show the expected results for a 10-minute period for all four Sound Level settings of Type 4226’s for tones of all frequencies. It is useful to note that, all things being equal, the measured noise dose is proportional to the measurement time, that is, the results shown in...

  • Page 32: Using The Ac Output

    Multifunction Acoustic Calibrator Type 4226 – User Manual Table 3.6 Expected changes in measured noise dose over a 10-minute period for IEC noise dose meters which record a 100% noise dose for 90 dB lasting 8 hours. Expected changes for all four settings of the Sound Level switch are...

  • Page 33: Using An External Generator

    Gen. using the push buttons. This is a useful feature in that alternative test signals Frequency Step may be used with Type 4226, for example, discrete tones not generated by Type 4226 or tones sweeping continuously in frequency. �� If the external signal exceeds 1.5 V, the Ext. Gen. LED will start flashing.
  • Page 34 Multifunction Acoustic Calibrator Type 4226 – User Manual...

  • Page 35: Maintenance And Service

    Maintenance and Service Storage and Handling The storage temperature of Type 4226 without a battery is from –25 to +70 °C (–13 to +158 °F). Exposure to rapid changes of humidity and temperature should be avoided. Before switching the instrument on, allow adequate time for any accumulated condensation to clear.
  • Page 36 Multifunction Acoustic Calibrator Type 4226 – User Manual...

  • Page 37: Specifications

    Chapter 5 Specifications Specifications – Multifunction Acoustic Calibrator Type 4226 All values are typical at 25 °C (77 °F), unless measurement LEVEL ACCURACY AT FIXED FREQUENCIES uncertainty is specified. All uncertainty values are specified at (linear and inverse A-weighting) 2 σ (that is, expanded uncertainty using a coverage factor of 2) Pressure Field (re 1 kHz): 31.5 Hz to 125 Hz:...
  • Page 38 Multifunction Acoustic Calibrator Type 4226 – User Manual Obtained Doses at 1 kHz: Standards Type 4226 complies with: SPL dB ANSI • IEC 60942-1988 Sound Calibrators, Class 1 (at reference 0.26% ±0.01% 0.18% ±0.01% sound pressure level) 2.62% ±0.20% 0.73% ±0.03% •...
  • Page 39 CHAPTER 5 Specifications Compliance with Standards China RoHS mark indicates compliance with administrative measures on the control of pollution caused by electronic information products according to the Ministry of Information Industries of the People’s Republic of China WEEE mark indicates compliance with the EU WEEE Directive Safety EN/IEC 61010–1: Safety requirements for electrical equipment for measurement, control and laboratory use...
  • Page 40 Multifunction Acoustic Calibrator Type 4226 – User Manual...

  • Page 41: Corrections And Adjustments

    The Sound Level in the Coupler – Using the Internal Signal Generator The following describes the corrections automatically applied to the calibration sound levels generated in the coupler and applies only when the switch on Type 4226 is set to Function Calibration.
  • Page 42 2.65 – When Type 4226 is used with its own internal signal generator, the accuracy of the corrected sound level generated in the coupler is assured for microphones listed under a, b and c categories. The basic formula for the actual sound level (LC) generated in the coupler loaded by...

  • Page 43: The Sound Level In The Coupler - Using An External Signal Generator

    Frequency response corrections are made automatically at each discrete frequency when Type 4226 uses its own internal signal generator, but not when an external generator is used. Therefore, they must be applied manually. Each Type 4226 and its coupler is a matched pair adjusted so that the sound level generated in the coupler is correct.
  • Page 44 Multifunction Acoustic Calibrator Type 4226 – User Manual...
  • Page 45 AC Out ............9, 12, 21 Falcon ...............10, 16 AC output ............4, 24 Fast time weighting ..........9 Acoustic calibrations ..........14 Free field (switch) ...........10 Adapter Free-field corrections ..........33 Connection ............14 Free-field responses ..........10 DP-0781 ............17 Frequency Hz ............8 AO-0481 ..............
  • Page 46 Standards ...............31 Storage ..............27 Noise dose meter ..........4, 23 Temperatures ............13 Output signal ............12 Test level ..............9 Test tonebursts ............19 Time weighting ............19 Peak/rms ratio ............21 Time weighting F ............9 Power ............... 8 Timer ..............11 Pressure response ........... 17, 34 Tolerances ............17, 18 Checks .............
  • Page 48 © Brüel & Kjær. All rights reserved. www.bksv.com...

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